1. Field of the Invention
This invention relates to code division multiple access (CDMA) mobile communication systems, and more particularly, to a modal adaptive antenna system and related signal receiving methods.
2. Description of the Related Art
In a classical operation of a smart antenna system, the array input vectors are applied to multipliers forming the adaptive array, a summing circuit and an adaptive processor for adjusting the weights.
The signals are multiplied by weighted outputs from the adaptive processor. It takes a long period of time for the adaptive processor to process the calculations in addition the adaptive processor is complicated. Consequently it is difficult to apply a classical scheme.
It is generally known in the art that these classical systems require extended periods of time for the adaptive processor to process calculations for signal receiving. Additionally, the circuit of the adaptive processor is complicated, and therefore it is difficult to apply the conventional smart antenna system to CDMA mobile communications.
More recently, demand has driven requirements for smart antenna systems configured for use in code division multiple access (CDMA) mobile communication systems and applications. In order to overcome some of the previous limitations, new and improved antenna systems and methods are being developed.
One example of a smart antenna receiver for use in CDMA applications is described in U.S. Pat. No. 6,353,643 by Park, hereinafter the '643 patent, the entire contents of which are hereby incorporated by reference. In the '643 patent, Park discloses a method for including the use of a pilot signal to enable a pseudo noise generator and re-inject the signal to get a more efficient method of control. Although Park suggests methods for improving prior art smart antenna systems, there is a continuing need for improved antenna systems and methods for increased efficiency in signal receiving.
Modernly, it is therefore a requirement in the dynamic field of mobile communications to provide improved and more efficient methods of signal receiving and processing. Current trends and demand in the industry continue to drive improvements in signal receiving and processing for mobile CDMA communications systems.